Antennas can be thought of as electric transducers, which can convert electric power into propagating radio waves. Antennas can be categorized into two groups, traveling wave antennas and resonant antennas. Traveling wave antennas utilize a guiding structure as the main method of radiation and are generally characterized by a matched termination. The current can be defined in terms of waves traveling in only one direction. Resonant antennas can be characterized by an open circuit; the main method of radiation for resonant antennas is through standing waves.
Antennas of either type usually have design features such as frequency of operation, bandwidth, and gain, which are directly related to its geometric shape and surface area. Current antenna design methodologies seek to optimize the geometric and volumetric shape/space for operation for a specified frequency, bandwidth, and required gain. This is mainly because in the prior art, the physical structure of the antenna, once defined, cannot be modified to operate at a different frequency, nor at a different bandwidth, nor at a different gain. Nearly all antennas are realized either in a planar form on a printed circuit board (PCB), or in some kind of solid structure such as a waveguide or a fiberglass dish. The antenna structure cannot be re-cast instantaneously if the operator desires a different operating frequency, bandwidth or gain.
In view of the above, it can be an object of the present invention to provide a software defined antenna, which can instantaneously change the antenna operating structure to achieve a design gain, operating frequency or bandwidth. Another object of the present invention can be to provide a software defined antenna that can arbitrarily change the conductive surface of the antenna according to the user's needs. Still another of the present invention can be to provide a software defined antenna that uses a projected or rastered image to photoconductively connect electrically isolated pixels to define an antenna on a conductive surface. Yet another object of the present invention can be to provide a software defined antenna that can accomplish beam steering without the use of mechanical components, and without manipulating changes in phase of the outgoing antenna beam. Still another object of the present invention can be to provide a software defined antenna that can be relatively easy to manufacture, that can be used in a cost-effective manner, and that can be durable.